Management of renal angiomyolipoma: a report of 53 cases

To evaluate the clinical, therapeutic and prognostic aspects of renal angiomyolipoma (AML) in patients either monitored by clinical and radiological follow-up or treated by surgical therapy.

Fifty-three patients with renal AML were divided in two groups; 33 patients in group 1 were monitored by annual clinical and ultrasonographic follow-up and 20 in group 2 were treated with surgical therapy. Two patients had tuberous sclerosis (TS) with synchronous bilateral and multiple lesions. Apart from the patients with TS, there were 38 lesions in group 1 and 25 in group 2. The mean (range) follow-up of group 1 was 60.2 (12-164) months.

In group 1, the diagnosis was most often incidental, after ultrasonography performed for symptoms unrelated to AML. In group 2, the suspicion of a malignant renal lesion, and spontaneous tumour rupture with bleeding and perirenal haematoma, were the main indications for surgical treatment. The mean lesion diameter was significantly greater in group 2 (5.4 cm) and in symptomatic patients (8.1 cm). In group 1, 92% of renal AMLs showed no radiographic changes, serious complications or new renal or extrarenal lesions during the follow-up. Only three lesions grew, after 22, 85 and 164 months, respectively. Of the 20 patients in group 2, 14 underwent conservative surgery.

Small (<4 cm) isolated AMLs, detected incidentally, showed a low risk of developing during long-term follow-up. Such patients may be followed conservatively by ultrasonography every 2 years. Spontaneous perinephric haemorrhage is related to the size of the lesion. When surgery is indicated (by symptoms or diagnostic doubt), a conservative procedure can be performed in most of cases.